1. Field of the Invention
The present invention relates to a circulating type milling apparatus for milling the keyway of a lock core at high speed.
2. Description of the Related Art
Taiwan Utility Model Publication No. 37696, entitled "AUTOMATIC MILLING DEVICE FOR LOCK CORES" and issued on Jun. 1, 1981, discloses a reciprocating cutter mounted on a movable base, a key being provided on the base for activating a control rod and a control arm for automatically urging a lock core to fall into a milling seat and thus be milled to form a keyway.
Taiwan Utility Model Publication No. 44973, entitled "MILLING DEVICE FOR LOCK CORES" and issued on Jul. 1, 1982, discloses a base with a cutter seat to which a cutter is mounted, and a motor is provided for driving a chain wheel. A milling seat frame and a milling seat are carried by a chain and thus conveyed along the conveying direction such that a lock core in the milling seat is milled by the cutter on the base to form a keyway.
It is, however, found that the milling speeds of the milling devices discloses in the above two disclosures are relatively low, only 3-4 lock cores are milled per minute. In addition, the whole cutter must be replaced if a small portion of the cutter is damaged, which is not economical.
Taiwan Utility Model Publication No. 300181, entitled "REVOLVER TYPE MILLING DEVICE FOR LOCK CORES" and issued on Mar. 11, 1997, discloses a frame with a revolver disc rotatably supported by a bearing and having posts for a working table that is moved vertically by a cylinder means. The revolver disc is attached to a shaft that is rotatably held by the bearing. A bevel gear is intermittently driven to cause the revolver disc to travel through a certain angle at regular time. A number of seats are mounted on the revolver disc for holding lock cores. When the working table is moved by the cylinder means, cutters on the working table mill the lock cores on the revolver disc in response to reciprocating movements of the posts of the frame, and the milling procedure on each lock core is continued when the revolver disc is rotated to next angular position to finally form a keyway on each lock core. It is, however, found that a tooth space difference exists when the lock core is turned, as the bevel gear is intermittently driven. Accordingly, the keyway formed by milling has a larger tolerance, resulting in lock cores with unreliable quality.
The present invention is intended to provide a circulating type milling apparatus for milling a lock core keyway that mitigates and/or obviates the above problems.